Risk Factors for Kaposi's Sarcoma-Associated Herpesvirus DNA in Blood and in Saliva in Rural Uganda

HIV-associated cancers and lymphoproliferative disorders caused by Kaposi sarcoma herpesvirus and Epstein-Barr virus

SUMMARYWithin weeks of the first report of acquired immunodeficiency syndrome (AIDS) in 1981, it was observed that these patients often had Kaposi sarcoma (KS), a hitherto rarely seen skin tumor in the USA. It soon became apparent that AIDS was also associated with an increased incidence of high-grade lymphomas caused by Epstein-Barr virus (EBV). The association of AIDS with KS remained a mystery for more than a decade until Kaposi sarcoma-associated herpesvirus (KSHV) was discovered and found to be the cause of KS. KSHV was subsequently found to cause several other diseases associated with AIDS and human immunodeficiency virus (HIV) infection. People living with HIV/AIDS continue to have an increased incidence of certain cancers, and many of these cancers are caused by EBV and/or KSHV. In this review, we discuss the epidemiology, virology, pathogenesis, clinical manifestations, and treatment of cancers caused by EBV and KSHV in persons living with HIV.

Is human herpesvirus 8 infection more common in men than in women? an updated meta-analysis

BACKGROUND

Clinically, most patients with Kaposi's sarcoma (KS) are male, and several direct and indirect mechanisms may underlie this increased susceptibility in men, Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is considered to be the primary etiological agent responsible for KS. Thus, we propose the hypothesis that men are more susceptible to HHV-8 infection, leading to a higher incidence of Kaposi's sarcoma among males. A meta-analysis was conducted to evaluate the association between gender and HHV-8 seropositivity in the general population.

METHODS

A comprehensive literature search was performed using 6 online databases: PubMed, EMBASE, Cochrane library, Web of Science, CNKI, and Wanfang. Studies published before March 15, 2023, were included.

RESULTS

In all, 33 articles including 41 studies were included in the meta-analysis. In the included adult population. men had a higher risk of HHV-8 infection than did women in adult populations from all over the world (odds ratio [OR]: 1.08, 95% confidence interval [CI]: 1.01-1.15), but no differences were found in child population from all over the world (OR: 0.90, 95% CI: 0.79-1.01). There was a significant difference in HHV-8 seroprevalence between men and women in sub-Saharan Africa (SSA) adult population (OR: 1.15, 95% CI: 1.05-1.26). However, no significant differences were observed in sub-Saharan Africa (SSA) child population (OR: 0.90, 95%CI 0.78-1.03). As for other continents, the results showed no significant difference, such as the Asian population (OR: 1.03, 95%CI: 0.92-1.16). or the European and American populations (OR 1.01, 95%CI 0.87-1.17).

CONCLUSION

There was a slight gender disparity for HHV-8 infection in the adult population. Among the adult populations from SSA and globally, men were more likely to be infected with HHV-8 than were women. However, no statistical significance was observed in the child populations from SSA and globally. In the future, the inclusion of more standardized studies may strengthen the results of this study.

Clinical and Demographic Factors Associated With Kaposi Sarcoma-Associated Herpesvirus Shedding in Saliva or Cervical Secretions in a Cohort of Tanzanian Women

Background

Reasons for the high prevalence of Kaposi sarcoma-associated herpesvirus (KSHV) in sub-Saharan Africa, and risk factors leading to viral reactivation and shedding, remain largely undefined. Preliminary studies have suggested that schistosome infection, which has been associated with impaired viral control, is associated with KSHV. In this study we sought to determine the relationship between active Schistosoma mansoni or Schistosoma haematobium infection and KSHV shedding.

Methods

We quantified KSHV DNA in saliva and cervical swabs from 2 cohorts of women living in northwestern Tanzanian communities endemic for S mansoni or S haematobium by real-time polymerase chain reaction. χ2 and Fisher exact tests were used to determine differences in clinical and demographic factors between those who were and were not shedding KSHV.

Results

Among 139 total women, 44.6% were KSHV seropositive. Six percent of those with S mansoni and 17.1% of those with S haematobium were actively shedding KSHV in saliva and none in cervical samples. Women from the S mansoni cohort who were shedding virus reported infertility more frequently (80% vs 19.5%, P = .009). There was no difference in frequency of KSHV salivary shedding between schistosome-infected and -uninfected women.

Conclusions

In an area with high KSHV seroprevalence and endemic schistosome infections, we provide the first report with data demonstrating no association between schistosome infection and salivary or cervical herpesvirus shedding. KSHV salivary shedding was associated with infertility, a known effect of another herpesvirus, human herpesvirus 6.

Immune cell phenotype and function patterns across the life course in individuals from rural Uganda

Background

To determine the pattern of immune cell subsets across the life span in rural sub-Saharan Africa (SSA), and to set a reference standard for cell subsets amongst Africans, we characterised the major immune cell subsets in peripheral blood including T cells, B cells, monocytes, NK cells, neutrophils and eosinophils, in individuals aged 3 to 89 years from Uganda.

Methods

Immune phenotypes were measured using both conventional flow cytometry in 72 individuals, and full spectrum flow cytometry in 80 individuals. Epstein-Barr virus (EBV) IFN-γ T cell responses were quantified in 332 individuals using an ELISpot assay. Full blood counts of all study participants were also obtained.

Results

The percentages of central memory (TCM) and senescent CD4+ and CD8+ T cell subsets, effector memory (TEM) CD8+ T cells and neutrophils increased with increasing age. On the other hand, the percentages of naïve T (TN) and B (BN) cells, atypical B cells (BA), total lymphocytes, eosinophils and basophils decreased with increasing age. There was no change in CD4+ or CD8+ T effector memory RA (TEMRA) cells, exhausted T cells, NK cells and monocytes with age. Higher eosinophil and basophil percentages were observed in males compared to females. T cell function as measured by IFN-γ responses to EBV increased with increasing age, peaking at 31-55 years.

Conclusion

The percentages of cell subsets differ between individuals from SSA compared to those elsewhere, perhaps reflecting a different antigenic milieu. These results serve as a reference for normal values in this population.

Plasmodium falciparum Malaria Is Associated With Increased Kaposi Sarcoma-Associated Herpesvirus (KSHV) Seropositivity and Higher KSHV Antibody Breadth and Magnitude: Results of a Case-Control Study From Rural Uganda

BACKGROUND

Previously, we showed that children with asymptomatic Plasmodium falciparum (Pf) malaria infection had higher Kaposi sarcoma-associated herpesvirus (KSHV) viral load, increased risk of KSHV seropositivity, and higher KSHV antibody levels. We hypothesize that clinical malaria has an even larger association with KSHV seropositivity. In the current study, we investigated the association between clinical malaria and KSHV seropositivity and antibody levels.

METHODS

Between December 2020 and March 2022, sick children (aged 5-10 years) presenting at a clinic in Uganda were enrolled in a case-control study. Pf was detected using malaria rapid diagnostic tests (RDTs) and subsequently with quantitative real-time polymerase chain reaction (qPCR). Children with malaria were categorized into 2 groups: RDT+/PfPCR+ and RDT-/PfPCR+.

RESULTS

The seropositivity of KSHV was 60% (47/78) among Pf-uninfected children, 79% (61/77) among children who were RDT-/PfPCR+ (odds ratio [OR], 2.41 [95% confidence interval {CI}, 1.15-5.02]), and 95% (141/149) in children who were RDT+/PfPCR+ (OR, 10.52 [95% CI, 4.17-26.58]; Ptrend < .001). Furthermore, RDT+/PfPCR+ children followed by RDT-/PfPCR+ children had higher KSHV IgG and IgM antibody levels and reacted to more KSHV antigens compared to uninfected children.

CONCLUSIONS

Clinical malaria is associated with both increased KSHV seropositivity and antibody magnitude, suggesting that Pf is affecting KSHV immunity.

Antibody profiling and predictive modeling discriminate between Kaposi sarcoma and asymptomatic KSHV infection

Protein-level immunodominance patterns against Kaposi sarcoma-associated herpesvirus (KSHV), the aetiologic agent of Kaposi sarcoma (KS), have been revealed from serological probing of whole protein arrays, however, the epitopes that underlie these patterns have not been defined. We recently demonstrated the utility of phage display in high-resolution linear epitope mapping of the KSHV latency-associated nuclear antigen (LANA/ORF73). Here, a VirScan phage immunoprecipitation and sequencing approach, employing a library of 1,988 KSHV proteome-derived peptides, was used to quantify the breadth and magnitude of responses of 59 sub-Saharan African KS patients and 22 KSHV-infected asymptomatic individuals (ASY), and ultimately to support an application of machine-learning-based predictive modeling using the peptide-level responses. Comparing anti-KSHV antibody repertoire revealed that magnitude, not breadth, increased in KS. The most targeted epitopes in both KS and ASY were in the immunodominant proteins, notably, K8.129-56 and ORF65140-168, in addition to LANA. Finally, using unbiased machine-learning-based predictive models, reactivity to a subset of 25 discriminative peptides was demonstrated to successfully classify KS patients from asymptomatic individuals. Our study provides the highest resolution mapping of antigenicity across the entire KSHV proteome to date, which is vital to discern mechanisms of viral pathogenesis, to define prognostic biomarkers, and to design effective vaccine and therapeutic strategies. Future studies will investigate the diagnostic, prognostic, and therapeutic potential of the 25 discriminative peptides.

Comparison of Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus viral load in peripheral blood mononuclear cells and oral fluids of HIV-negative individuals aged 3-89 years from Uganda

We previously found that age, sex and malaria were associated with KSHV in individuals from Uganda. In this study, we have evaluated these same factors in relation to EBV in the same specimens. Overall, 74% (oral fluids) and 46% (PBMCs) had detectable EBV. This was significantly higher than observed for KSHV (24% oral fluids and 11% PBMCs). Individuals with EBV in PBMCs were more likely to have KSHV in PBMCs (P = 0.011). The peak age for detection of EBV in oral fluids was 3-5 years while that of KSHV was 6-12 years. In PBMCs, there was a bimodal peak age for detection of EBV (at 3-5 years and 66 + years) while for KSHV there was a single peak at 3-5 years. Individuals with malaria had higher levels of EBV in PBMCs compared to malaria-negative individuals (P = 0.002). In summary, our results show that younger age and malaria are associated with higher levels of EBV and KSHV in PBMCs suggesting malaria impacts immunity to both gamma-herpesviruses.

Distinctive Kaposi Sarcoma-Associated Herpesvirus Serological Profile during Acute Plasmodium falciparum Malaria Episodes

The seroprevalence of Kaposi sarcoma-associated herpesvirus (KSHV) and the incidence of endemic Kaposi sarcoma (KS) overlap with regions of malaria endemicity in sub-Saharan Africa. Multiple studies have shown an increased risk of KSHV seroconversion in children from high malaria compared to low malaria regions; however, the impact of acute episodes of Plasmodium falciparum (P. falciparum) malaria on KSHV's biphasic life cycle and lytic reactivation has not been determined. Here, we examined KSHV serological profiles and viral loads in 134 children with acute malaria and 221 healthy children from high malaria regions in Kisumu, as well as 77 healthy children from low malaria regions in Nandi. We assayed KSHV, Epstein-Barr virus (EBV), and P. falciparum malaria antibody responses in these three by multiplexed Luminex assay. We confirmed that KSHV seroprevalence was significantly associated with malaria endemicity (OR = 1.95, 1.18-3.24 95% CI, p = 0.01) with 71-77% seropositivity in high-malaria (Kisumu) compared to 28% in low-malaria (Nandi) regions. Furthermore, KSHV serological profiles during acute malaria episodes were distinct from age-matched non-malaria-infected children from the same region. Paired IgG levels also varied after malaria treatment, with significantly higher anti-ORF59 at day 0 but elevated ORF38, ORF73, and K8.1 at day 3. Acute malaria episodes is characterized by perturbation of KSHV latency in seropositive children, providing further evidence that malaria endemicity contributes to the observed increase in endemic KS incidence in sub-Saharan Africa.

Comparison of Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus viral load in peripheral blood mononuclear cells and oral fluids of HIV-negative individuals aged 3 to 89 years from Uganda

We previously found that age, sex, and malaria were associated with KSHV viral load in individuals from Uganda. In this study, we have evaluated factors associated with presence of EBV DNA in blood and oral fluids among the same individuals, using the same biological samples. Overall, 74% of oral fluids samples and 46% of PBMCs had detectable EBV, compared to 24% and 11% for KSHV respectively Individuals with EBV in PBMCs were more likely to have KSHV in PBMCs (P=0.016). The peak age for detection of EBV in oral fluids was 3-5 years while that of KSHV was 6-12 years. In PBMCs, the peak age for detection of EBV was 66+ years and KSHV was 3-5 years. Individuals with malaria had higher levels of EBV in PBMCs compared to malaria-negative individuals (P=0.002). In summary, our results show that younger age and malaria are associated with higher levels of EBV and KSHV in PBMCs suggesting malaria impacts immunity to EBV and KSHV.

CE: HIV-Associated Kaposi Sarcoma in the Combination Antiretroviral Therapy Era

ABSTRACT

Kaposi sarcoma is a tumor caused by Kaposi sarcoma herpesvirus, also known as human herpesvirus 8. Its occurrence is associated with an immunocompromised state. Kaposi sarcoma that occurs among people living with HIV (PLWH) is known as epidemic Kaposi sarcoma. Despite the decline in HIV-associated complications because of the introduction of combination antiretroviral therapy two decades ago, Kaposi sarcoma continues to affect PLWH worldwide. It affects young African American men more than other age and racial groups and can result in multiorgan dysfunction, leading to short-term and chronic debilitating symptoms as well as death. While some patients with epidemic Kaposi sarcoma are managed as outpatients, others may require higher levels of care and their acuity may fluctuate throughout their life span. Therefore, nurses, regardless of their specialty, may experience caring for a patient with epidemic Kaposi sarcoma at some point in their career. Learning about this condition and the needs of patients who have it will help nurses provide effective care. Here, the authors describe Kaposi sarcoma in general as well as the epidemiology, characteristics, and management of epidemic Kaposi sarcoma. They also describe specific nursing considerations in the care of PLWH who have the disease.

KSHV (HHV8) vaccine: promises and potential pitfalls for a new anti-cancer vaccine

Seven viruses cause at least 15% of the total cancer burden. Viral cancers have been described as the "low-hanging fruit" that can be potentially prevented or treated by new vaccines that would alter the course of global human cancer. Kaposi sarcoma herpesvirus (KSHV or HHV8) is the sole cause of Kaposi sarcoma, which primarily afflicts resource-poor and socially marginalized populations. This review summarizes a recent NIH-sponsored workshop's findings on the epidemiology and biology of KSHV as an overlooked but potentially vaccine-preventable infection. The unique epidemiology of this virus provides opportunities to prevent its cancers if an effective, inexpensive, and well-tolerated vaccine can be developed and delivered.

The implications of cell-free DNAs derived from tumor viruses as biomarkers of associated cancers

Cancer is still ranked as a leading cause of death according to estimates from the World Health Organization (WHO) and the strong link between tumor viruses and human cancers have been proved for almost six decades. Cell-free DNA (cfDNA) has drawn enormous attention for its dynamic, instant, and noninvasive advantages as one popular type of cancer biomarker. cfDNAs are mainly released from apoptotic cells and exosomes released from cancer cells, including those infected with viruses. Although cfDNAs are present at low concentrations in peripheral blood, they can reflect tumor load with high sensitivity. Considering the relevance of the tumor viruses to the associated cancers, cfDNAs derived from viruses may serve as good biomarkers for the early screening, diagnosis, and treatment monitoring. In this review, we summarize the methods and newly developed analytic techniques for the detection of cfDNAs from different body fluids, and discuss the implications of cfDNAs derived from different tumor viruses in the detection and treatment monitoring of virus-associated cancers. A better understanding of cfDNAs derived from tumor viruses may help formulate novel anti-tumoral strategies to decrease the burden of cancers that attributed to viruses. This article is protected by copyright. All rights reserved.

Whole-genome sequencing of Kaposi sarcoma-associated herpesvirus (KSHV/HHV8) reveals evidence for two African lineages

Kaposi sarcoma (KS)-associated herpesvirus (KSHV/HHV-8) was first sequenced from the body cavity (BC) lymphoma cell line, BC-1, in 1996. Few other KSHV genomes have been reported. Our knowledge of sequence variation for this virus remains spotty. This study reports additional genomes from historical US patient samples and from African KS biopsies. It describes an assay that spans regions of the virus that cannot be covered by short read sequencing. These include the terminal repeats, the LANA repeats, and the origins of replication. A phylogenetic analysis, based on 107 genomes, identified three distinct clades; one containing isolates from USA/Europe/Japan collected in the 1990s and two of Sub-Saharan Africa isolates collected since 2010. This analysis indicates that the KSHV strains circulating today differ from the isolates collected at the height of the AIDS epidemic. This analysis helps experimental designs and potential vaccine studies.

Prevalence and correlates of Kaposi's sarcoma-associated herpesvirus and herpes simplex virus type 2 infections among adults: evidence from the NHANES III data

BACKGROUND

Kaposi's sarcoma-associated herpes virus (KSHV) prevalence and risk factors exhibit considerable variations across populations in different geographic regions. Determinants and the transmission routes of KSHV infection are uncertain. We seek to identify the possible risk factors and the transmission routes of KSHV infection in non-endemic areas.

METHODS

We collected annual cases and seroprevalence of KSHV and herpes simplex virus type 2 (HSV-2) from the NHANES III sampled individuals from the US general population (1988-1994). We included 13,179 and 10,720 individuals with available remaining serum samples of KSHV and HSV-2. Logistic regression was employed to explore potential risk factors for the seropositivity.

RESULTS

The seroprevalence was 2.05% for KSHV infection and 31.03% for HSV2 infection among this population. All risk factors of sexual behaviors included were strongly associated with HSV-2 positive, however, only MSM had an approximately fivefold increased risk of KSHV infection (OR = 4.71; 95%CI 1.61 11.30). Mexican Americans (2.51%) and older (chi-squaretrend =  - 6.71, P < 0.001) individuals had a higher risk of KSHV infection. After adjustment, individuals with higher level of education and economic status had lower KSHV infection.

CONCLUSIONS

In non-endemic areas, KSHV transmission may be related to sexual activity in men, especially in male homosexuals. Higher education level and economic status are protective factors for KSHV infection.

Kaposi's sarcoma-associated herpesvirus T cell responses in HIV seronegative individuals from rural Uganda

T cell responses to Kaposi's sarcoma-associated herpesvirus (KSHV) are likely essential in the control of KSHV infection and protection from associated disease, but remain poorly characterised. KSHV prevalence in rural Uganda is high at >90%. Here we investigate IFN- γ T cell responses to the KSHV proteome in HIV-negative individuals from a rural Ugandan population. We use an ex-vivo IFN- γ ELISpot assay with overlapping peptide pools spanning 83 KSHV open reading frames (ORF) on peripheral blood mononuclear cells (PBMC) from 116 individuals. KSHV-specific T cell IFN- γ responses are of low intensity and heterogeneous, with no evidence of immune dominance; by contrast, IFN- γ responses to Epstein-Barr virus, Cytomegalovirus and influenza peptides are frequent and intense. Individuals with KSHV DNA in PBMC have higher IFN- γ responses to ORF73 (p = 0.02) and lower responses to K8.1 (p = 0.004) when compared with those without KSHV DNA. In summary, we demonstrate low intensity, heterogeneous T cell responses to KSHV in immune-competent individuals.

Malaria Is Associated With Kaposi Sarcoma-Associated Herpesvirus Seroconversion in a Cohort of Western Kenyan Children

BACKGROUND

We aimed to determine whether Plasmodium falciparum infection affects age of Kaposi sarcoma-associated herpesvirus (KSHV) seroconversion in Kenyan children.

METHODS

Kenyan children (n = 144) enrolled at age 1 month, from 2 sites with different levels of malaria transmission (stable/high vs unstable/low) were followed to age 24 months. Plasma was tested for KSHV antibodies using enzyme-linked immunosorbent assay (ELISA; K8.1 and LANA) and a multiplex bead-based assay (K8.1, K10.5, ORF38, ORF50, and LANA) and whole blood tested for P. falciparum DNA using quantitative PCR. Cox proportional hazards models were used to assess associations between P. falciparum DNA detection, malaria annualized rate (P. falciparum detections/person-years), and enrollment site (malaria-high vs malaria-low) with time to KSHV seroconversion.

RESULTS

KSHV seroprevalence was 63% by age 2 years when assessed by multiplex assay. Children with P. falciparum were at increased hazards of earlier KSHV seroconversion and, among children with malaria, the hazard of becoming KSHV seropositive increased significantly with increasing malaria annualized rate. Children from the malaria-high transmission region had no significant difference in hazards of KSHV seroconversion at 12 months but were more likely to become KSHV seropositive by age 24 months.

DISCUSSION

Malaria exposure increases the risk for KSHV seroconversion early in life.

Malaria during pregnancy and transplacental transfer of Kaposi sarcoma-associated herpesvirus (KSHV) antibodies: a cohort study of Kenyan mother and child pairs

BACKGROUND

Kaposi sarcoma-associated herpesvirus (KSHV) seroprevalence in sub-Saharan African children can range up to 50% by age 2 years but factors affecting early age of KSHV infection are not well understood. Malaria during pregnancy has been associated with hindered transplacental transfer of antibodies to several pathogens but whether it affects transplacental transfer of KSHV antibodies is unknown. We aimed to determine if in utero malaria exposure reduced the transfer of KSHV antibodies across the placenta.

METHODS

A cohort study in Kisumu, Kenya enrolled pregnant women at their first antenatal clinic (ANC) visit and followed them through delivery. We included 70 KSHV-positive, HIV-negative mothers and their children. KSHV antibody levels were measured by ELISA (K8.1, ORF73) and multiplex assay (K8.1, ORF73, K10.5, ORF38, ORF50). Transplacental transfer of antibodies was measured by the cord to maternal blood ratio (CMR) of KSHV antibodies. Malaria during pregnancy was defined as detection of Plasmodium falciparum (Pf) DNA at any ANC visit or delivery. Among women with malaria during pregnancy, we examined time of last malaria infection prior to delivery (< 27 vs. 27+ weeks gestation) and malaria incidence rate (MIR) (episodes/100 person-weeks).

RESULTS

KSHV seroprevalence (positive for K8.1 or ORF73 by ELISA) among pregnant women was 88%. Neither malaria during pregnancy, malaria infection timing, nor MIR were associated with maternal delivery KSHV antibody blood levels. Maternal delivery and cord blood KSHV antibody levels were highly correlated but these correlations did not differ by malaria during pregnancy. KSHV transplacental antibody transfer was not associated with malaria during pregnancy, malaria infection timing, nor MIR.

CONCLUSIONS

Malaria during pregnancy does not appear to affect transfer of KSHV antibodies across the placenta.

Variation in KSHV prevalence between geographically proximate locations in Uganda

Kaposi's sarcoma-associated herpesvirus (KSHV) transmission within endemic areas may vary. KSHV seroprevalence has been studied by different groups of researchers using different methods, making it difficult to make direct comparisons. Here we show results on KSHV seroprevalence using the same laboratory method from four different but geographically proximate populations in Uganda. Blood samples from the urban Entebbe Mother and Baby Study (EMaBS), the rural General Population Cohort (GPC), the fishing community Lake Victoria Island Intervention Study on Worms and Allergy related Diseases (LaVIISWA) and the high-risk sexual behaviour Good Health for Women Project (GHWP), were tested for IgG antibody levels to K8.1 and ORF73 recombinant proteins using ELISA. All adult participants of the EMaBS study and the GHWP were women, while the GPC (54% female) and LaVIISWA (52% female) studies had both males and females. EMaBS children were all 5 years of age while their mothers were 14 to 47 years of age. GHWP women were 15 to 45 years old, LaVIISWA participants were 1 to 72 years old while GPC participants were 1 to 103 years old. KSHV seropositivity varied in the different populations. In children aged 5 years, EMaBS had the lowest prevalence of 15% followed by GPC at 35% and LaVIISWA at 54%. In adult women, seropositivity varied from 69% (EMaBS) to 80% (LaVIISWA) to 87% (GPC) to 90% (GHWP). The reasons for the variation in prevalence are unclear but may reflect differences in the prevalence of cofactors between these four geographically proximate populations.

Cancer Risk Studies and Priority Areas for Cancer Risk Appraisal in Uganda

Background

Research into aetiologies and prevention of the commonest cancers and implementation of primary and secondary prevention can reduce cancer risk and improve quality of life. Moreover, monitoring the prevalence of cancer risk factors in a specific population helps guide cancer prevention and early detection efforts and national cancer control programming.

Objective

This article aims to provide the scope and findings of cancer risk studies conducted in Uganda to guide researchers, health-care professionals, and policymakers.

Methods

Between November 2019 to January 2020, we searched peer-reviewed published articles in Pubmed, EMBASE and Cochrane Library (Cochrane central register of controlled trials-CENTRAL). We followed the recommendation of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - the PRISMA. The primary focus was to identify cancer risk and prevention studies conducted in Uganda and published in peer-reviewed journals from January 2000 and January 2020. We used key Boolean search terms with their associated database strings.

Results

We identified 416 articles, screened 269 non-duplicate articles and obtained 77 full-text articles for review. Out of the 77 studies, we identified one (1%) randomized trial, two (2.5%) retrospective cohort studies and 14 (18%) case-control studies, 46 (60%) cross-sectional studies, five (6.4%) ecological studies, three panel studies (4%) and six (8%) qualitative studies. Cervical cancer was the most studied type of cancer in Uganda (23.4%, n = 18 studies), followed by lymphomas - both Hodgkin and Non-Hodgkin sub-types (20.7%), n = 16 studies) and breast cancer (15.6%, n = 12 studies). In lymphoma studies, Burkitt lymphoma was the most studied type of lymphoma (76%, n = 13 studies). The studies concentrated on specific cancer risk awareness, risk perceptions, attitudes, uptake of screening, uptake of human papillomavirus vaccination, the prevalence of some of the known cancer risk factors and obstacles to accessing screening services.

Conclusion

The unmet need for comprehensive cancer risk and prevention studies is enormous in Uganda. Future studies need to comprehensively investigate the known and putative cancer risk factors and prioritize the application of the higher-hierarchy evidence-generating epidemiological studies to guide planning of the national cancer control program.